Formula Used
To calculate concrete volume in cubic yards:
Volume (yards) = (Length × Width × Thickness) ÷ 27
All measurements must be in feet
For a 10×10 slab at 4 inches thick: (10 × 10 × 0.33) ÷ 27 = 1.23 cubic yards
Concrete Needed by Thickness
| Thickness | Cubic Yards | 80lb Bags |
|---|---|---|
| 4 inches | 1.23 yd³ | ~56 bags |
| 5 inches | 1.54 yd³ | ~70 bags |
| 6 inches | 1.85 yd³ | ~84 bags |
When to Use Each Thickness
4 inches
Best for patios, walkways, and light-duty applications
5 inches
Suitable for light driveways and moderate traffic areas
6 inches
Required for heavy vehicles, RVs, and commercial use
Cost Estimate
Average concrete cost ranges from $120–$170 per cubic yard depending on your location and mix specifications.
Total Cost for 10×10 Slab:
- • 4 inches thick: $150–$210
- • 5 inches thick: $185–$260
- • 6 inches thick: $220–$315
These estimates include the concrete only. Additional costs may include delivery fees, labor, site preparation, and finishing work.
Tips Before Ordering
- • Always round up your order – It's better to have extra concrete than to run short
- • Consider reinforcement – Add rebar or wire mesh for added strength and crack prevention
- • Account for uneven ground – Low spots will require more concrete than calculated
- • Check minimum orders – Many suppliers have minimum delivery requirements
- • Prepare the site – Have forms, gravel base, and tools ready before delivery
Frequently Asked Questions
How many bags of concrete for 10x10 slab?
About 56–84 bags of 80lb concrete mix depending on thickness. For 4 inches thick, you'll need approximately 56 bags. For 6 inches thick, you'll need about 84 bags.
Should I order extra concrete?
Yes – always order at least 5–10% more concrete than calculated. This accounts for waste, spillage, uneven ground, and measurement variations. It's much better to have leftover concrete than to run short mid-pour.
Is it cheaper to mix bags or order ready-mix?
For a 10×10 slab, ready-mix concrete is typically more cost-effective and saves significant labor. Bagged concrete costs about $180–$270 per cubic yard versus $120–$170 for ready-mix delivery.
What thickness should I use for a patio?
4 inches is standard for patios and walkways. This provides adequate strength for foot traffic and outdoor furniture without unnecessary expense.